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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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f0c328f8af
For the problem of increasing fragmentation of the bpf loader programs, instead of using bpf_loader.o, which is used in samples/bpf, this commit refactors the existing tracepoint tracing programs with libbbpf bpf loader. - Adding a tracepoint event and attaching a bpf program to it was done through bpf_program_attach(). - Instead of using the existing BPF MAP definition, MAP definition has been refactored with the new BTF-defined MAP format. Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200823085334.9413-4-danieltimlee@gmail.com
252 lines
5.7 KiB
C
252 lines
5.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <sched.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <locale.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <sys/wait.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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static int cstate_map_fd, pstate_map_fd;
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#define MAX_CPU 8
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#define MAX_PSTATE_ENTRIES 5
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#define MAX_CSTATE_ENTRIES 3
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#define MAX_STARS 40
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#define CPUFREQ_MAX_SYSFS_PATH "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq"
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#define CPUFREQ_LOWEST_FREQ "208000"
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#define CPUFREQ_HIGHEST_FREQ "12000000"
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struct cpu_stat_data {
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unsigned long cstate[MAX_CSTATE_ENTRIES];
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unsigned long pstate[MAX_PSTATE_ENTRIES];
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};
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static struct cpu_stat_data stat_data[MAX_CPU];
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static void cpu_stat_print(void)
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{
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int i, j;
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char state_str[sizeof("cstate-9")];
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struct cpu_stat_data *data;
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/* Clear screen */
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printf("\033[2J");
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/* Header */
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printf("\nCPU states statistics:\n");
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printf("%-10s ", "state(ms)");
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for (i = 0; i < MAX_CSTATE_ENTRIES; i++) {
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sprintf(state_str, "cstate-%d", i);
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printf("%-11s ", state_str);
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}
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for (i = 0; i < MAX_PSTATE_ENTRIES; i++) {
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sprintf(state_str, "pstate-%d", i);
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printf("%-11s ", state_str);
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}
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printf("\n");
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for (j = 0; j < MAX_CPU; j++) {
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data = &stat_data[j];
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printf("CPU-%-6d ", j);
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for (i = 0; i < MAX_CSTATE_ENTRIES; i++)
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printf("%-11ld ", data->cstate[i] / 1000000);
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for (i = 0; i < MAX_PSTATE_ENTRIES; i++)
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printf("%-11ld ", data->pstate[i] / 1000000);
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printf("\n");
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}
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}
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static void cpu_stat_update(int cstate_fd, int pstate_fd)
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{
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unsigned long key, value;
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int c, i;
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for (c = 0; c < MAX_CPU; c++) {
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for (i = 0; i < MAX_CSTATE_ENTRIES; i++) {
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key = c * MAX_CSTATE_ENTRIES + i;
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bpf_map_lookup_elem(cstate_fd, &key, &value);
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stat_data[c].cstate[i] = value;
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}
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for (i = 0; i < MAX_PSTATE_ENTRIES; i++) {
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key = c * MAX_PSTATE_ENTRIES + i;
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bpf_map_lookup_elem(pstate_fd, &key, &value);
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stat_data[c].pstate[i] = value;
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}
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}
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}
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/*
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* This function is copied from 'idlestat' tool function
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* idlestat_wake_all() in idlestate.c.
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*
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* It sets the self running task affinity to cpus one by one so can wake up
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* the specific CPU to handle scheduling; this results in all cpus can be
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* waken up once and produce ftrace event 'trace_cpu_idle'.
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*/
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static int cpu_stat_inject_cpu_idle_event(void)
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{
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int rcpu, i, ret;
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cpu_set_t cpumask;
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cpu_set_t original_cpumask;
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ret = sysconf(_SC_NPROCESSORS_CONF);
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if (ret < 0)
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return -1;
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rcpu = sched_getcpu();
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if (rcpu < 0)
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return -1;
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/* Keep track of the CPUs we will run on */
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sched_getaffinity(0, sizeof(original_cpumask), &original_cpumask);
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for (i = 0; i < ret; i++) {
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/* Pointless to wake up ourself */
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if (i == rcpu)
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continue;
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/* Pointless to wake CPUs we will not run on */
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if (!CPU_ISSET(i, &original_cpumask))
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continue;
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CPU_ZERO(&cpumask);
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CPU_SET(i, &cpumask);
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sched_setaffinity(0, sizeof(cpumask), &cpumask);
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}
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/* Enable all the CPUs of the original mask */
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sched_setaffinity(0, sizeof(original_cpumask), &original_cpumask);
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return 0;
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}
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/*
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* It's possible to have no any frequency change for long time and cannot
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* get ftrace event 'trace_cpu_frequency' for long period, this introduces
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* big deviation for pstate statistics.
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*
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* To solve this issue, below code forces to set 'scaling_max_freq' to 208MHz
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* for triggering ftrace event 'trace_cpu_frequency' and then recovery back to
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* the maximum frequency value 1.2GHz.
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*/
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static int cpu_stat_inject_cpu_frequency_event(void)
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{
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int len, fd;
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fd = open(CPUFREQ_MAX_SYSFS_PATH, O_WRONLY);
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if (fd < 0) {
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printf("failed to open scaling_max_freq, errno=%d\n", errno);
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return fd;
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}
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len = write(fd, CPUFREQ_LOWEST_FREQ, strlen(CPUFREQ_LOWEST_FREQ));
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if (len < 0) {
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printf("failed to open scaling_max_freq, errno=%d\n", errno);
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goto err;
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}
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len = write(fd, CPUFREQ_HIGHEST_FREQ, strlen(CPUFREQ_HIGHEST_FREQ));
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if (len < 0) {
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printf("failed to open scaling_max_freq, errno=%d\n", errno);
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goto err;
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}
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err:
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close(fd);
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return len;
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}
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static void int_exit(int sig)
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{
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cpu_stat_inject_cpu_idle_event();
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cpu_stat_inject_cpu_frequency_event();
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cpu_stat_update(cstate_map_fd, pstate_map_fd);
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cpu_stat_print();
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exit(0);
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}
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int main(int argc, char **argv)
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{
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struct bpf_link *link = NULL;
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struct bpf_program *prog;
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struct bpf_object *obj;
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char filename[256];
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int ret;
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snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
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obj = bpf_object__open_file(filename, NULL);
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if (libbpf_get_error(obj)) {
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fprintf(stderr, "ERROR: opening BPF object file failed\n");
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return 0;
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}
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prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
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if (!prog) {
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printf("finding a prog in obj file failed\n");
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goto cleanup;
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}
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/* load BPF program */
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if (bpf_object__load(obj)) {
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fprintf(stderr, "ERROR: loading BPF object file failed\n");
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goto cleanup;
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}
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cstate_map_fd = bpf_object__find_map_fd_by_name(obj, "cstate_duration");
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pstate_map_fd = bpf_object__find_map_fd_by_name(obj, "pstate_duration");
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if (cstate_map_fd < 0 || pstate_map_fd < 0) {
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fprintf(stderr, "ERROR: finding a map in obj file failed\n");
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goto cleanup;
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}
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link = bpf_program__attach(prog);
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if (libbpf_get_error(link)) {
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fprintf(stderr, "ERROR: bpf_program__attach failed\n");
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link = NULL;
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goto cleanup;
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}
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ret = cpu_stat_inject_cpu_idle_event();
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if (ret < 0)
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return 1;
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ret = cpu_stat_inject_cpu_frequency_event();
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if (ret < 0)
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return 1;
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signal(SIGINT, int_exit);
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signal(SIGTERM, int_exit);
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while (1) {
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cpu_stat_update(cstate_map_fd, pstate_map_fd);
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cpu_stat_print();
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sleep(5);
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}
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cleanup:
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bpf_link__destroy(link);
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bpf_object__close(obj);
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return 0;
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}
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